.  s.  r  /  i 


Circular  No.  159.  !«-it-i 

United  States  Department  of  Agriculture, 

BUREAU   OF  ENTOMOLOGY. 
L.   O.   HOWARD,    Entomologist  and   Chief  of  Bureau. 


DA1AGE  TO  THE  WOOD  OF  FIRE-KILLED  DOUGLAS  FIB, 
ami  METHODS  OF  PREVENTING  LOSSES,  IN  WESTERN 
\\  A8HINGTON    \M>  OREGON. 

Bj    i    D    Hopkins, 
In  (hurt!-   of  Forest  Insect  Investigations. 

Inquiries,  with  specimens,  relating  to  extensive  damage  to  fire- 
killed  Douglas  Br  in  western  Washington  showed  i!i<'  importance 
of  making  available  to  our  correspondents  some  information  based 
the  results  of  forest  insed  investigations 

Douglas-fir  timber  killed  by  fire  is  attacked  by  a  class  <>f  wood- 
boring  insects  which  extend  their  burrows  through  the  sound  sap- 
and  heartwood  and  thus  contribute  to  the  rapid  deterioration 
and  decay  of  i  kind  of  resource  which  otherwise  would  be  available 
for  utilization  during  the  period-  of  from  1  to  20  years  or  more  after 
death  of  the  trees,  depending  on  the  tree-  and  character  of  product 
desired.  This  loss  often  amounts  to  from  25  to  LOO  per  cent  during 
the  period  in  which  the  dead  timber  would  otherwise  be  almost  as 
valuable  as  Living  timber. 

Whenever  the  dying  ami  dead  timber  is  available  for  utilization 
within  one  to  -i\  or  more  years,  much,  and  sometimes  practically  all, 
of  the  loss  due  to  wood-boring  insects  i*  preventable. 

One  class  <>f  wood-borers  attacks  the  timber  during  the  spring, 
Bummer,  and  fall  months  within  the  first  week  or  two  after  the  tire 
or  after  the  tree-  begin  to  die.  hut  rarely  continue-  to  work  m  the 
wood  for  more  than  one  year,  and  all  of  some  forms  of  the  damage, 
ially  to  the  sapwood,  i-  caused  within  •">"  to  60  day-,  while  other 
forms  continue  during  the  warm  season  <>f  the  first  <•!•  second  year. 
depending  en  the  date  of  the  tire  and  the  species  of  insect  involved. 
Most  of  the  damage  is  usually  confined  to  the  sapwood,  hut  some  of 
it  may  extend  into  the  heartwood. 

1  Revised   elrcuUr  letter  of  .Tune   16  -it   to  Interested   timber  land  owners.    It   Is 

here    published    to   supplement    I  -  tin    112   OB   1  .1    Doaglaj    Fir. 

and    r.ureau    of    Bntomology    areolar    127,    Insert    Injuries    to    the    Wood    of    Dying   and 
Dead    l 

50687'— Clr.  1 ."  0 —  1 2 


2  DAMAGE   TO    WOOD   OF   FIRE-KILLED   DOUGLAS   FIR. 

Another  class  of  wood-boring  insect.-,  represented  by  a  number  of 
species,  attacks  the  trees  three  or  four  year-  after  they  die;  these  bore 
deep  into  the  heartwood,  thus  causing  serious  damage.  Insects  of 
this  class  will  continue  to  attack  the  trees  year  after  year  as  long  as 
they  find  sound  wood  in  which  to  excavate  their  burrows.  There- 
fore the  damage  increases  year  by  year  until  the  wood  is  rendered 
entirely  worthless  by  the  borings  and  by  the  subsequent  decay  which 
necessarily  follows. 

It  is  a  fact,  however,  that  there  is  often  a  great  difference  in  the 
relative  damage  to  individual  trees  which  have  died  from  injuries 
caused  by  the  same  fire.  Some  trees  will  be  ruined  in  a  few  years. 
while  others  will  be  but  slightly  damaged  and  remain  sound  for  10, 
20,  or  even,  in  exceptional  cases,  50  years. 

The  date  or  period  of  the  fire  or  fires  is  an  important  factor  in  rela- 
tion to  subsequent  injury  by  insects.  It  is  well  known  that  timber 
killed  by  fire  at  some  seasons  of  the  year  will  remain  sound  much 
longer  than  that  killed  at  other  seasons. 

The  character  of  the  primary  injury  and  the  date  or  season  of  the 
subsequent  death  of  the  individual  trees  is  also  important.  Some  of 
the  trees  will  die  immediately  after  the  fire,  while  others  will  die  at 
intervals  for  a  year  or  more.  Those  dying  at  different  times  and 
seasons  will  show  very  different  conditions  as  to  subsequent  damage 
by  wood-boring  insects.  Then,  again,  different  ages  and  types  of 
trees  of  the  same  species  will  show  very  different  rates  of  damage,  as 
will  also  different  species  of  trees. 

It  is  somewhat  different  in  the  case  of  timber  killed  by  bark- 
beetles  or  defoliating  insects,  because  in  such  cases  the  timber  usually 
dies  within  definite  periods  and  is  therefore  subject  to  attack  by 
special  kinds  of  wood-boring  insects. 

REQUISITES  FOR  SUCCESS  IX  PREVENTING  LOSSES. 

In  regard  to  methods  of  preventing  losses  from  damage  by  wood- 
boring  insects  to  fire-killed  timber  there  are  a  few  fundamental 
requisites  for  success  which  should  be  carefully  considered  before 
action  is  taken.  Among  these  are  the  recognition  of  the  different 
classes  of  injury  and  of  the  importance  of  expert  advice  on  some 
of  the  essential  details  in  any  plans  for  extensive  operations  to  pre- 
vent losses. 

CLASSES    OF    INSECTS    AND    INJURY. 

Some  of  the  important  classes  of  insects  and  injury  are  as  follows: 
(1)   Certain  pinhole  borers  (ambrosia  beetles)  attack  the  sapwood 

as  soon  as  the  trees  begin  to  die,  but  the  damage  by  this  class  of 

borers  is  usually  limited  to  the  first  season. 


l>\\i  UJE    1 1.   w  OOD  01    I  11:1    KI1  i  ED   D01  01  \      I  lit.  .5 

(2)  Certain  species  and  classes  of  bark  and  wood  boring  grubs 
hatch  from  eggs  deposited  in  the  bark  of  the  trees  and  burrow  under 

the  bark  for  m  time  before  thej  enter  the  \n < m •. I .    Soi pecies  do  uot 

go  beyond  the  sapwood,  while  others  bore  deep  into  the  heartwood. 

(8)  Certain  stages  and  classes  of  bark-boring  grubs  hatching  from 
deposited  in  the  hark  attack  the  dying  and  dead  trees,  but  never 
enter  the  \\  ood. 

ili  Certain  species  and  classes  <>l'  wood-boring  grubs  attack  the 
aapwood  of  trees  dead  one  to  (luce  years  :i 1 1>  1  confine  their  borings 
to  the  sap*  ood. 

Certain  species  and  classes  of  wood-boring  grubs  and  other 
insects  enter  the  wood  of  i  rees  dead  three  to  twentj  years  or  more  and 
bore  deep  into  the  heart w I. 

["IONS  GOVERNING   II  i  I   WORK  OF  I  \-l.<   rS  01  rHE  DIFFERENT  CI   \--i  - 

i  A)  In  classes  1  to  I.  inclusive,  the  presence  of  hark  on  the  trunks 
of  the  tree-  i-.  with  a  few  exceptions,  necessary  as  a  receptacle  for 
the  eggs  and  as  the  first  food  of  the  young  grubs.  The  exceptions  are 
the  pinhole  borers  or  ambrosia  beetles,  which  will  sometimes  attack 
the  wood  when  the  hark  i-  removed,  although  the  wood  must  be  in  a 
moist  condition.  The  hark-,  however,  oiler-  far  more  favorable  con- 
ditions for  the  work  of  this  class  of  insects  because  it  provide.-  for  a 
continued  moist  condition  of  the  wood 

I '.  |  In  class  5  the  hark  is  not  essential.  Although  offering  favor- 
able condition-  for  the  attack  of  some  species  of  insects,  it  i-  not 
necessary  for  the  attack  of  others,  especially  after  the  sapwood  begins 
to  decay. 

GENES  W.    Ml  TH0D8  OF   <  ONTROI* 

l]  I  ion    A. 

To  avoid  damage  from  wood-boring  insects  which  are  dependent 
upon  condition  A.  one  or  more  of  the  following  general  methods 
should  he  adopted,  SO  far  a-  the  local  facilities  and  cost  w  ill  permit  : 

(a)  Prompt  utilization  of  the  timber  within  30  to  60  day-  after 
it  is  killed  by  lire  any  time  from  the  beginning  of  the  growth  of 
vegetation  in  the  spring  until  it  stops  in  the  fall,  which  will  vary 
with  latitude  ami  altitude.  Timber  killed  after  the  first  snow  or 
heavy  fro-t  should  he  utilized  within  30  day-  after  plant  activity 
-tarts  in  the  following  spring  if  deterioration  is  to  be  prevented. 

(b)  Prompt  removal  of  the  hark-  from  the  merchantable  timber 
under  the  same  requirements  a-  to  periods  mentioned  under   I 

Placing  the  unbarked  h><j^  in  water  under  the  same  require- 
ments as  to  periods  mentioned  under  (a). 


UNIVERSITY  OF  FLORIDA 


4  DAMAGE   TO   WOOD   OF   FIBE-KII  3  1262  09216  6098 

In  addition  to  the  general  requirements  of  the  principal  method* 
(a,  b,  and  c),  each  of  classes  1,  2,  3,  and  4,  and  each  of  the  many 
species  of  each  class  require  some  different  or  specific  detail  in  the 
method  to  insure  the  best  success.  Therefore  when  it  is  desired  to 
avoid  a  special  class  of  injury  expert  advice  should  be  secured. 

Condition  B. 

Under  condition  B  the  opportunities  are  much  less  favorable  for 
the  prevention  of  further  losses.  After  the  timber  has  been  dead 
three  to  twenty  years  or  more,  one  or  more  of  the  following  methods 
should  be  considered  and  adopted  whenever  practicable. 

MERCHANTABLE    TIMBER    DEAD    THREE   TO    FIVE    YEARS. 

(d)  Timber  dead  three  to  five  years  should  be  cut  and  converted 
into  lumber  with  as  little  delay  as  possible,  or 

(e)  Cut  into  logs  and  placed  in  water,  to  remain  there  until  it 
can  be  converted  into  lumber  or  other  products. 

MERCHANTABLE  TIMBER  DEAD  SIX  TO  TEN   YEARS  OB  LONGEB. 

(/)  Thoroughly  inspect  individual  trees  to  locate  and  mark  those 
that  are  yet  available  for  utilization,  and  make  estimates  on  which 
to  base  conclusions  as  to  whether  or  not  it  can  be  profitably  logged 
for  direct  utilization  or  storage  in  water. 

Approved : 

James  Wilson, 

Secretary  of  Agriculture. 
Washington,  D.  C.  May  16,  1912. 


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